Hydrogels Based on Cross-Linked Cationic Cellulose Derivatives
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Chemistry of Natural Compounds, Vol. 56, No. 6, November, 2020
HYDROGELS BASED ON CROSS-LINKED CATIONIC CELLULOSE DERIVATIVES
S. M. Butrim,* T. D. Bil′dyukevich, N. S. Butrim, and T. L. Yurkshtovich
Cationization of wood and cotton celluloses using 3-chloro-2-hydroxypropyltrimethylammonium chloride in aqueous suspensions in the presence of various amounts of NaOH followed by cross-linking with epichlorohydrin was studied in detail. The compositions of the cationic cellulose ethers and the reaction efficiency depended strongly on the ratio of the alkylating mixture components. The physicochemical properties of the synthesized samples were studied using chemical analysis, IR spectroscopy, X-ray structure analysis, and centrifugation to determine water absorption. The content of cationic groups and concentration of cationic cellulose in the epichlorohydrin cross-linking stage had decisive effects on the degree of swelling in water and aqueous NaCl solution of the cross-linked cationic cotton and wood celluloses. Keywords: cationic cellulose, cross-linking, hydrogel, amorphization, degree of swelling. Polysaccharides can be functionalized using a wide variety of chemical reactions (oxidation, formation of ethers and esters) because of the presence of reactive hydroxyls in them [1–3]. The physical and chemical properties of the obtained derivatives depend on not only the molecular mass and supramolecular structure but also the substituents, their number, and their positions along the polymer chain. These features and the increased emphasis on the discovery of new materials are responsible for the interest in controlled modifications applicable to polysaccharides. The literature teaches that various types of cellulose, e.g., cotton, wood, bacterial, microcrystalline, ramie, annual plants, etc., can be used as starting material to prepare hydrogels from it and its derivatives [4, 5]. However, many researchers have shown that hydrogels based on native cellulose have water absorption less than 20–30 g/g, which is not always effective, while hydrogels based on cellulose derivatives can absorb much more (50–500 g/g and greater) water while retaining the required gel strength and absorption rate of aqueous solution. This allows them to be considered superabsorbents. CH2OH O OH
O
Cl
OH
OH
CH3
OH
CH2 OH O O
N CH3Cl
CH2 OR O
CH3
OR
a
OH
CH2 OR O OR
O OR
O OR
I CH2OR O
CH2OR O
OR O
OR
O O
Cl
O OR R=
CH2 O O
OR
OR II
N CH3Cl
or
H
CH3
CH2 OR O
O OR
CH3
OH
OH
b
OH O
R1 =
OH
OR1
a. 18% NaOH, 20–60°C; b. 7% NaOH, 60°C Research Institute for Physical Chemical Problems, Belarusian State University, Minsk, 220006, e-mail: [email protected]. Translated from Khimiya Prirodnykh Soedinenii, No. 6, November–December, 2020, pp. 949–952. Original article submitted February 19, 2020. 1106
0009-3130/20/5606-1106
©2020
Springer Science+Business Media, LLC
TABLE 1. Preparation Conditions and Physicochemical Properties of Cationic Wood and Cotton Celluloses (tcat. = 24 h) Cellulose type Sulfite wood
Cati
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